What you are discribing is a 'quilt as you go' method. It just means that you are not working with the full quilt, batt and/or backing. There are numerous techniques. If you do a search on 'quilt as you go' or QAYG, on this board, lots of links will come up. This is a good way to quilt a large quilt on a domestic machine. If you try one method and don't like it, try another, it's really worth the effort.